The present invention relates to a novel use of a combination of the plants Ginseng, more precisely Panax ginseng, and Ginkgo, more precisely Ginkgo biloba and/or the combination of extracts of both plants to improve cognitive skills. The combination is useful for improving the speed of memory and memory quality in normal, healthy subjects as well as to prevent deterioration of the speed of memory in people with decreased cognitive functions as well as to counteract cognitive fatigue.
Extracts of Ginkgo biloba contain ginkgo-flavone glycosides and terpenoids which are known to have vaso-regulating and blood viscosity decreasing properties. The main indications for which Ginkgo is prescribed in Western countries, such as France and Germany, are intermittent claudication and cerebral insufficiency.
The roots of Panax ginseng C. A. Meyer contain several triterpene glycosides named ginsenosides (or panaxosides) which are believed to contribute to the adaptogenic and physical performance enhancing properties of the ginseng extracts. It is used to treat anemia, diabetes mellitus, insomnia, neurasthenia, gastritis, abnormal blood pressure, dyspepsia, overstrain and fatigue.
Petkov et al. disclose that the standardized extracts of Panax ginseng, Ginkgo biloba and a combination thereof improve the learned behavior of young and old rodents(Petkov, V. D. et al., Planta Med. 59 (1993) pp. 106-114). This study showed that the combination of Panax ginseng and Ginkgo biloba did not exhibit a synergistic effect compared with the single active principles in rats.
It has previously been suggested (Moss and Scholey, Psychopharmacology, 1996 124(3):255-60, Kennedy and Scholey, Psychopharmacology, 2000 149(1):63-71) that some demanding cognitive tasks may be facilitated by the simple augmentation of delivery of metabolic substrates to the brain. As an example, a previous study from this laboratory (Kennedy and Scholey Psychopharmacology, 2000 149(l):63-71) investigated the relationship between heart rate, blood glucose levels and performance on a xe2x80x9cdemandingxe2x80x9d mental arithmetic task (serial verbal subtraction of 7 from a given number between 800 and 1000; xe2x80x9cserial 7sxe2x80x9d), a xe2x80x9cless demandingxe2x80x9d mental arithmetic task (serial subtraction of 3; xe2x80x9cserial 3sxe2x80x9d), and a long term verbal memory task. It was found that not only did both serial subtraction tasks engender significant increases in heart rate above that engendered by somatically identical counting tasks, but that performance on both was also related to the magnitude of fall in blood glucose levels during task performance. Performance on the most demanding task (serial 7s) was also not only improved by a glucose drink, but was also related to resting heart rate.
Unexpectedly, it was found in cognitive tests that administering a combination of extracts of the root of Panax ginseng C. A. Meyer and of the leaves of Ginkgo biloba to humans positively effects cognitive skills, for example, such as the speed and quality of memory in normal, healthy subjects. Both Panax ginseng and Ginkgo biloba have been extensively used for various indications in Chinese medicine and are described in the traditional Chinese Pharmacopoeia. Ginkgo extracts and Ginseng extracts are known to have effects on cognitive functions, yet the effects produced by the combination are of a novel type.
Therefore the present invention is directed to a method to enhance the speed of memory and memory quality in normal, healthy subjects comprising the administration of a medication and/or a dietary supplement containing a combination of Ginseng and Ginkgo. Further, the combination may be used to prevent deterioration of the speed of memory in people with decreased cognitive functions and to counteract cognitive fatigue. Specifically, the composition of the present invention consists of herbal ingredients, for example, derived by an extraction from Ginseng roots and Ginkgo leaves. Another aspect of the present invention is a method for the enhancement of the mental effort and/or cognitive performance, in particular of children or young adults, said method comprising co-administration of synergistically enhancing amounts of the plant Panax ginseng, extracts thereof and/or the principle active substances thereof and the plant Ginkgo biloba, extracts thereof and/or the principle active substances thereof to a person in acute need of such treatment.
The Ginseng extract contains among other substances ginsenosides and polysaccharides, while the Ginkgo extract contains among other substances ginkgo flavone glycosides and terpene lactones. While all these substances are known to have pharmacological activities, the range of their pharmacological actions has not yet been fully elucidated, but in vitro studies indicate that some of them have antioxidant properties and that they inhibit platelet aggregation, while others exert an action on the oxygen uptake in the cells and others again may exert an immunomodulating action. It is considered, however, that only complete extracts prepared according to the methods set out in this invention possess the activities necessary to achieve the effects related to this invention.
It is a primary object of the present invention to provide a method to improve the speed of memory and memory quality in normal, healthy subjects, to prevent deterioration of the speed of memory in people with decreased cognitive functions and to counteract cognitive fatigue. It is a further object of the present invention to provide a method for improving the speed of memory and to prevent a decrease of the speed of memory by taking formulations comprising herbal ingredients, wherein the medication and/or the dietary supplement is manufactured pursuant to a controlled process that preserves the herbal curing qualities of the ingredients. It is still a further object of the present invention to provide a method for improving the speed of memory and to prevent a decrease of the speed of memory comprising herbal ingredients and having minimal or no side effects and thus being safe for internal consumption.